Exhaust pipe silencers with telescoped gas passage tubes



Jan. 17, 1967 F. E. DEREMER I 3,298,458

EXHAUST PIPE SILENGERS WITH TELESCOPED GAS PASSAGE TUBES Filed Oct. 4, 1965 oacaq oaool INVENTOR.

EA/0: Q M071 4TTOPA/EY United States Patent 3,298,458 EXHAUST FEE SILENCERS WITH TELESCOPED GAS PASSAGE TUBES Floyd E. Deremer, Livonia, Mich, assignor to Oldberg Manufacturing Company, Grand Haven, Mich, a corporation of Michigan Filed Get. 4, 1965, Ser. No. 492,528 16 Claims. (Cl. 18154) This invention relates to a method, system and apparatus for attenuating sound waves in gas streams and more especially to a method of and apparatus for attenuating sound waves in an exhaust gas stream from an internal combustion engine of an automotive vehicle.

It has been conventional practice in automotive vehicles powered by internal combustion engines to convey exhaust gases from the engine exhaust manifold or manifolds through a sound attenuating mother or silencer thence through a tail pipe connected with the muffler for discharging the exhaust gases rearwardly of the vehicle. The mufiiers or silencers heretofore used have been from two to four feet or more in length depending upon the interior gas passage and sound attenuating construction of the mufller.

The trend in automotive vehicle design has recently been toward lowering the vehicle silhouette, necessitating the use of more transverse chassis frame members beneath the vehicle floor.

This type of construction increases the difficulties of providing mufflers of sufficient length to properly attenuate the broad range of sound waves of an exhaust gas stream from the engine. Such trend in vehicle design has fostered the use of an exhaust pipe extending from the engine exhaust manifold substantially full length of the vehicle with sound attenuating means or units in the tube disposed in spaced relation so as to more effectively attenuate sound waves of the exhaust gas stream. My application, Serial Number 228,131, filed October 3, 1962 issued into Patent 3,219,142, discloses a construction of exhaust pipe embodying spaced sound attenuating means.

The present invention embraces a method or system enabling the resonator units or sound attenuating means to be adjusted or tuned whereby improved attenuation of sound waves in an exhaust gas stream is achieved.

Another object of the invention resides in a system embodying individual sound attenuating units in spaced relation along a tubular gas passage means wherein the sound attenuating units may be of different lengths and adjusted or tuned to attenuate a particular range of sound waves or frequencies to attain more efiective attenuation.

Another object of the invention is the provision of resonator or sound attenuator units arranged to be spaced lengthwise of a gas passage means or exhaust pipe wherein each resonator unit embodies telescoping gas passage tubes of different diameters arranged in aligned relation, the tubes being in overlapping relation, the adjustment or extent of overlap providing a means for tuning the resonator for the most efficient attenuation of certain sound waves in an exhaust gas stream.

Another object of the invention resides in the use of a series of individual sound attenuating means spaced lengthwise of a gas conveying means or exhaust pipe wherein the exhaust gases of an exhaust gas stream move in rectilinear directions through the spaced attenuating means in combination with a combined baffle and resonator construction associated with the exhaust pipe retard flow of exhaust gases as well as to attenuate sound waves of low frequencies.

Another object of the invention is the provision of a muffler or resonator construction for use with a gas passage means or exhaust pipe embodying lengthwise spaced 3,298,458 Patented Jan. 17, 1967 attenuator units, the resonator construction embodying perforated baffle means for dispersing gases of the stream over a substantial area, the resonator construction incorporating a tuning or resonance tube for attenuating sound waves.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is an elevational view of a gas passage means or exhaust pipe with spaced sound attenuating means;

FIGURE 2 is an enlarged sectional view of one form of sound attenuating means or unit of the invention embodying overlapping tuning tubes;

FIGURE 3 is an enlarged end view of the construction shown in FIGURE 2;

FIGURE 4 is an elevational view illustrating an exhaust gas passage means embodying a resonator of the character shown in FIGURE 2 and embodying a resonator chamber and baffle construction;

FIGURE 5 is a sectional view through the resonator chamber construction shown in FIGURE 4, the section being taken substantially on the line 55 of FIGURE 4, and

FIGURE 6 is a transverse view partly in section taken substantially on the line 6-6 of FIGURE 5.

Referring to the drawings, FIGURE 1 illustrates a gas passage means which, in the embodiment illustrated in FIGURE 1, is a tubular gas conveying means or exhaust pipe 20 in which is disposed in lengthwise spaced relation, two or more individual sound attenuating means or units 22, 24 and 26 as illustrated in FIGURE 1.

The left-hand end of the tubular means or exhaust pipe 20 is adapted to be connected with the exhaust gas manifold (not shown) of an internal combustion engine of a vehicle whereby the exhaust gases from the engine are conveyed through gas passage means in the sound attenuating means and the exhaust pipe for discharge from the distal end 32 thereof at the rear of the automotive vehicle.

The tubular means or exhaust pipe 20 is bent or shaped as indicated at regions 28 and 30 to avoid interference with chassis frame members or other components of the vehicle and may be of various shapes depending upon the particular chassis frame construction of the vehicle with which the exhaust pipe and sound attenuation construction is used.

FIGURES 2 and 3 illustrate one of the sound attenuating units 22 within the tubular means or exhaust pipe 20 in enlarged cross section, the units 24 and 26 being of similar construction. The sound attenuating unit .22 contained within the exhaust pipe 20 comprises an outer tube or tubular member 32, an inner gas passage tube 34 and an intermediate gas passage tube 36. The intermediate shell or tubular member 36 is of lesser diameter than the tubular member 32 to provide therebetween an annular space 38. The innermost tubular member 34 is of lesser diameter than the diameter of the intermediate tube 36 to provide an annular space 40 between the overlapping telescoped regions of the tubes 34 and 36.

As shown in FIGURE 2, the innermost tube or tubular member 34 is supported by spaced inwardly extending annular portions or partitions 42 which are fashioned by forcing metal of the tube 32 inwardly to provide the partitions or supports 42, which are spaced lengthwise and engage the exterior cylindrical surface of the innermost tube 34 for supporting the tube. tube 32 at regions 44 extends slightly outwardly and engages the inner cylindrical surface of the tubular means or exhaust pipe 20.

The metal of the tube 32 at lengthwise spaced regions extends inwardly to engage the outer cylindrical surface of the tube 36 and form partitions 46 in the annular space 38.

The metal of the tube 32 extends slightly outwardly as at 49 to engage the tubular means or exhaust pipe 20. The partitions 42 and 46 provide annularly-shaped sound attenuating chambers 50, 51 and 52 for attenuating high frequency sound waves.

The extent of telescoping overlap of the intermediate tube 36 with the innermost tube 34, which provides the annular passage or opening 40, may be adjusted or controlled to vary the range of attenuation of low frequency sound waves. The broken lines at 34' illustrate an adjusted position of the tube 34 lengthwise with respect to the tube 36 to vary the extent of overlap of the tubes. Within certain limits, the greater the overlap of tubes 34 and 36, the more effective the sound attenuation of low frequency sound waves.

By adjusting the relative lengthwise positions of the tubes 34 and 36, the amount of overlap may be varied to provide a simple, yet effective method and means of varying the range of attenuation of low frequency sound waves. The chamber 51 becomes a substantially closed low frequency resonance chamber. A wall area of the innermost tube 34 is provided with a substantial number of small openings or perforations 54 which establishes communication with the high frequency attenuating chamber 50.

A wall area of the intermediate tube 36 is likewise provided with a substantial number of small openings or perforations 56 for establishing communication with the high frequency attenuating chamber 62. The small openings 54 and 56 provide acoustic couplings with the sound attenuating chambers 50 51 and 52. The overlapping portions of tubes 34 and 36 need not be perforated or provided with openings as they would serve no useful purpose at the region of overlap.

In the use of the attenuating unit 22, shown in FIG- URES 2 and 3, the gases from the exhaust manifold of the engine enter the gas passage tube 34 through the left-hand end of the tube as viewed in FIGURE 2 as 7 well as through the small openings 54 in communication with an annular-region 58 adjacent the left-hand partition 42. The exhaust gases flow through the tube 34 and high frequency sound waves are attenuated through the acoustic couplings 54 in communication with the high frequency sound attenuating chamber 50.

The gases moving through the gas passage tube 34 flow into the gas passage tube 36, the small openings or acoustic couplings 56 establishing communication with the high frequency attenuating chamber 52 for attenuating high frequency sounds. The resonance chamber 51 functions to attenuate low frequency sound waves in the exhaust gas stream.

The following is a typical example of diameters of the tubular components and chambers shown in FIGURES 2 and 3. The tubes are made of comparatively thin sheet metal such as sheet steel.

The exterior diameter of the innermost or first gas passage tube 34 may be approximately one-half inch in diameter and the interior diameter of the second or intermediate gas passage tube 36 may be from about one and three-fourths inches to two inches in diameter. Taking into consideration the thickness of the sheet metal, the annular space 40 at the overlapping region of the tubes 34 and 36 provides an annular space or passage of about one-eighth to three-sixteent'hs of an inch surrounding the tube 34.

The metal of the.

This annular passage 40 is the entrance or communication region for the low frequency resonance chamber 51. As previously mentioned, the range of low frequency sound waves attenuated or dissipated in the low frequency resonance chamber 51 may be varied by the amount or extent of overlap between the tubes 34 and 36. It is found that the tubes may be overlapped a lengthwise distance of from about one-fourth of an inch to about 'five inches depending upon the frequency of the sound waves to be attenuated in the resonance chamber The attenuating unit 26, shown in FIGURE 1, may be of the same or similar construction as the attenuating unit 22 shown in detail in FIGURES 2 and 3. The attenuating unit 24 contained within the tubular means or exhaust pipe 20 may be of greater length depending upon the range of frequency of sound waves to be attenuated, but is of the same character as the attenuating means shown in FIGURES 2 and 3. It is found that individual sound attenuating means or units may be between ten and twenty-four inches in length but may be of greater or lesser length if desired for particular sound attenuating purposes.

While it is found preferable to utilize an exhaust pipe 20 comprising a one piece full length tube about two and one quarter inches in diameter, it is to be understood that the tubular means or regions of the exhaust pipe adjacent each attenuating unit may be substantially equal in length to the attenuating unit and such lengths of pipe joined with coupling pipes, such as the pipe configurations adjacent the regions 28 and 30 by welding pipe lengths 20 adjacent the attenuating units to the coupling pipes to thereby provide a continuous imperforate outermost tubular means or exhaust pipe.

FIGURES 4, 5 and 6 illustrate the use in the sound attenuating system of a transversely extending resonance or resonator chamber or small muffler construction 74 that may be used in conjunction with or in addition to one or more sound attenuating units such as units 22, 24 or 26. The tubular means or exhaust pipe 20' adjacent the bent configuration 28' or adjacent another region of the exhaust pipe may be equipped with the low frequency resonator 74. The resonator 74 comprises a sheet metal housing 76, preferably of oval shape as shown in FIGURE 6, having end walls 78 and 80.

The engine side of the exhaust pipe 20' is in registration with an opening 82 in the end wall and is welded thereto to admit exhaust gases into the resonator 74. The rear portion of the exhaust pipe 20 is in registration with an outlet opening 84 in the wall 78 and is welded thereto for conveying exhaust gases through an attenuating unit such as the attenuating unit 26', shown in FIGURE 4.

It is to be understood that the portion of the exhaust pipe 20 between the resonator and the engine exhaust manifold may be equipped with one or more sound atten- Hating units of the character shown in FIGURES 2 and 3.

Disposed within the resonator 74 in a plane transversely of the axis of adjacent regions of the exhaust pipe 20' is a partition or baffle 86 having an area preferably provided with small gas passages, orifices or perforations 88 to accommodate exhaust gas flow through the resonator 74 but providing some dispersion of the gases and obtaining some sound attenuation by obstruction. The partition divides the resonator 74 into two chambers 92 and 94 the partition being adjustable for varying the sizes of the chambers, if desired. Mounted in an opening in the partition 86 at a region out of alignment with the exhaust gas pipe 20' is a resonating or tuning tube having its ends spaced from the end walls 78 and 80 of the resonator 74.

The tube 90serves to attenuate low frequency sound waves and may be varied in length depending upon the sound frequencies to be attenuated. If desired, the tube 90 may have its wall area provided with perforations supplementing the openings 88 in the partition as an addedgas transfer means from one side of the partition 86 to the other.

In the use of the arrangement shown in FIGURES 4 through 6, the exhaust gases from exhaust manifold of an engine are directed through one or more attenuating units of the character shown in FIGURE 2 disposed in the exhaust pipe 21 in advance of the delivery of the gases into the small mufiler or resonator 74.

The gas enters the resonator 74 from the left as viewed in FIGURE 5, from the exhaust pipe. Some of the exhaust gases in the first chamber M provided by the partition 86 are dispersed over the perforated area of the partition and some of the gases flow through the orifices 88 in the partition and through the tube 90.

The resonator tube 90 attenuates low frequency sound waves entrained in the gas stream as well as to provide added means for conveying exhaust gas from the chamber 92 into the chamber 94 at the right-hand side of the partition 86, the exhaust gases flowing out of the chamber 94 through the exhaust pipe section 20 rearwardly of the resonator. The exhaust gases discharged from the resonator 74 flow through the sound attenuating unit 26 and thence discharge to the atmosphere through the open end 32'. Thus, the resonator 74 provides a means, in addition to the sound attenuators of the character shown in FIGURE 2, for attenuating sound waves in an exhaust gas stream.

It will be apparent from the foregoing that an exhaust gas conveying means or exhaust pipe is provided wherein sound attenuating units of the character shown in FIG- URES 2 and 3 may be tuned to attenuate certain sound frequencies by varying the extent of overlap of the gas passage tubes in each attenuating means so as to exercise control over the attenuation of sound waves of different lengths or frequencies thereby rendering possible the attenuation of sound waves over a greater range without increasing the lengths of individual attenuating units such as that shown in FIGURES 2 and 3, and without unduly extending the length of the exhaust pipe.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

1 claim:

1. An exhaust gas conveying means for attachment directly to the exhaust manifold of a vehicle engine including, in combination, an outermost tubular means, a plurality of sound attenuating means in lengthwise spaced relation within the tubular means, each of said attenuating means including a tubular member within the tubular means, a first gas passage tube in the tubular member of lesser diameter than the tubular member providing a space therebetween, a second gas passage tube of lesser diameter than the first gas passage tube within the tubular member and disposed in aligned relation with the first gas passage tube, lengthwise spaced partition means between the tub-ular member and the gas passage tubes supporting said tubes, and a wall area of each of said tubes being perforated with small openings.

2. The combination according to claim 1 wherein the second gas passage tube extends into and in overlapping relation with the first gas passage tube providing an annular space between the tubes at the overlapping region.

3. The combination according to claim 1 wherein integral portions of the tubular member extend inwardly into engagement with said tubes, said inwardly extending portions providing the lengthwise spaced partition means.

4. The combination according to claim 1 wherein the tubular member and the gas passage tubes are of sheet metal.

5. The combination according to claim 2 wherein the second gas passage tube is adjustable lengthwise with respect to the first gas passage tube to vary the extent of overlap of said tubes.

6. The combination according to claim 2 wherein the lengthwise spaced partition means provides with said gas passage tubes lengthwise spaced high frequency sound attenuating chambers and an intermediate low frequency resonator chamber at the overlapping regions of the gas passage tubes.

7. An exhaust gas conveying means for attachment dimctly to the exhaust manifold of a vehicle engine including an outermost tubular means, a plurality of sound attenuating means arranged in lengthwise spaced relation within the tubular means, each of said sound attenuating means including a tubular member telescoped within the tubular means, a first tube of lesser diameter than the interior diameter of the tubular member providing an annular space between the first tube and the tubular member, said first tube being of lesser length than the tubular member, a second tube within the tubular member of lesser diameter than the interior diameter of the first tube, said second tube being of lesser length than said tubular member, said first and second tubes being in lengthwise overlapping relation throughout a portion of their lengths, each of said gas passage tubes having a wall area provided with a plurality of small openings, and lengthwise spaced partition means between said tubes and the tubular member supporting said tubes.

8. The combination according to claim 7 wherein the partition means comprises inwardly extending portions integral with the tubular member, one of said gas passage tubes being adjustable relative to the other for varying the extent of overlap of the gas passage tubes.

9. A sound attenuating means adapted for insertion in an exhaust pipe connected with an exhaust manifold of a vehicle engine including, in combination, a tubular member, a first gas passage tube in the tubular member of lesser diameter than the tubular member providing a space therebetween, a second gas passage tube of lesser exterior diameter than the interior diameter of the first gas passage tube extending into and in overlapping relation with a portion of the first gas passage tube providing an annular passage between the overlapping regions of said gas passage tubes, lengthwise spaced partition means integrally formed on the tubular member and extending inwardly into engagement with the gas passage tubes supporting said tubes, and a wall area of each of said tubes being perforated with small openings forming acoustic couplings with the regions between the gas passage tubes and the tubular member.

10. The combination according to claim 9 wherein one of the gas passage tubes is adjustable lengthwise relative to the other for tuning the range of sound frequency attenuation of the chamber at the overlapping region of said gas passage tubes.

11. An exhaust gas conveying means for attachment directly to the exhaust manifold of a vehicle engine including, in combination, an outermost tubular means, a plurality of sound attenuating means in lengthwise spaced relation within the tubular means, each of said attenuating means including a tubular member within the tubular means, a first gas passage tube in the tubular member of lesser diameter than the tubular member providing a space therebetween, a second gas passage tube of lesser diameter than the first gas passage tube extending into and in overlapping relation with a portion of the first gas passage tube, lengthwise spaced partition means between the tubular member and the gas passage tubes supporting said tubes, and a wall area of each of said tubes being perforated with small openings, a transversely extending housing of sheet metal connected with the outermost tubular means intermediate the ends thereof, a partition of sheet metal in said housing, said partition providing two chambers in the housing, and a resonator tube opening into the chambers.

12. The combination according to claim 11 wherein the partition is disposed in a plane normal to the adjacent regions of the tubular means, said resonator tube being disposed in an opening in the partition and supported by the partition.

13. An exhaust gas conveying means for attachment directly to the exhaust manifold of a vehicle engine including a tubular means, a plurality of sound attenuating means arranged in lengthwise spaced relation within the tubular means, a transversely extending housing of sheet metal connected with the tubular means intermediate its ends at a region spaced from the sound attenuating means, a partition in said housing provided with a plurality of small gas passage openings, and a resonator tube extended through the partition and supported intermediate its ends by said partition, said housing providing a resonator chamber means for attenuating low frequency sound Waves.

14. The combination according to claim 13 wherein the tubular means is an exhaust pipe, and the sound attenuating means comprises individual sound attenuating units inserted in the exhaust pipe.

15. The combination according to claim 11 wherein the partition in the housing is provided with gas passage openings.

16. The combination according to claim 11 wherein the partition in the housing is adjustable for varying the sizes of the chambers provided therein.

References Cited by the Examiner UNITED STATES PATENTS 2,147,015 2/1939 Deremer 181-353 2,189,425 2/1940 Leadbetter 18 135 .2 2,332,543 10/1943 Wilson 18148 2,337,299 12/1943 Noblitt et a1. 18154 2,357,792 9/ 1944 Powers 181-48 2,403,699 7/ 1946 Wilson 18164.1 3,104,733 9/ 1963 Ludlow 181-36.2 3,104,735 9/1963 Ludlow et al. 18136.2 3,112,007 11/1963 Ludlow et al 18136.2 3,209,858 10/ 1965 Jettingholf 18161 X FOREIGN PATENTS 484,771 5/1938 Great Britain. 167,485 6/ 1959 Sweden.

RICHARD B. WILKINSON, Primary Examiner.

R. S. WARD, Assistant Examiner. 

1. AN EXHAUST GAS CONVEYING MEANS FOR ATTACHMENT DIRECTLY TO THE EXHAUST MANIFOLD OF A VEHICLE ENGINE INCLUDING, IN COMBINATION, AN OUTER MOST TUBULAR MEANS, A PLURALITY OF SOUND ATTENUATING MEANS IN LENGTHWISE SPACED RELATION WITHIN THE TUBULAR MEANS, EACH OF SAID ATTENUATING MEANS INCLUDING A TUBULAR MEMBER WITHIN THE TUBULAR MEANS, A FIRST GAS PASSAGE TUBE IN THE TUBULAR MEMBER OF LESSER DIAMETER THAN THE TUBULAR MEMBER PROVIDING A SPACE THEREBETWEEN, A SECOND GAS PASSAGE TUBE OF LESSER DIAMETER THAN THE FIRST GAS PASSAGE TUBE WITHIN THE TUBULAR MEMBER AND DISPOSED IN ALIGNED RELATION WITH THE FIRST GAS PASSAGE TUBE, LENGTHWISE SPACED PARTITION MEANS BETWEEN THE TUBULAR MEMBER AND THE GAS PASSAGE TUBES SUPPORTING SAID TUBES, AND A WALL AREA OF EACH OF SAID TUBES BEING PERFORATED WITH SMALL OPENINGS. 